SZ-2 keeps getting better: Improvements to the SZ-2 Algorithm

SZ-2 (Sachidananda-Zrnić phase coding with 2 scans) processing, operationally deployed on the WSR-88D system in 2017, helps to mitigate range/velocity ambiguity. The implementation of SZ-2 involves a split-cut scan strategy (i.e., two 360-degree azimuth scans) with the first scan uniformly sampled with a long PRT, Surveillance scan, for unambiguous long-range coverage followed by a second scan with phase-coded uniformly sampled shorter PRT, Doppler scan, for near-unambiguous velocity coverage. The use of SZ(8/64) phase coding in the Doppler scan allows for separation of overlaid Doppler velocity and spectrum width. The RDA Build 22 update to the SZ-2 algorithm incorporates new censoring rules and integrates Coherency-Based Thresholding, the Hybrid Spectrum Width estimator, the Hybrid-Scan Estimators (non-operational), and ground-clutter-mitigation. In this work, we describe the updates and present the performance of the proposed SZ-2 algorithm upgrades using archived WSR-88D data.